The invention concerns a bondhead for a Wire Bonder.
Wire Bonders are used for the production of wire connections between a semiconductor chip and a substrate. Most of the Wire Bonders available on the market today move the bondhead in the horizontal xy plane by means of two orthogonally arranged drives. An example of such a drive system is revealed in the patent specification EP 317 787. This drive system also uses air bearings charged by means of vacuum. A considerable disadvantage of this well-known Wire Bonder exists in that when moving the bondhead to a new position relatively large masses must be accelerated. This requires powerful drive systems and robust bearings. A further disadvantage exists in that, depending on the position of the bondhead, on accelerating the bondhead relatively large torques occur which place great demands on the bondhead bearings. This sets limits on the maximum possible acceleration values and therefore the production rate of the Wire Bonder.
A Wire Bonder is known from the patent specification U.S. Pat. No. 5,330,089 with which movement of the bondhead takes place with a polar drive system. With this drive system relatively large masses must also be accelerated. The load to be accelerated by the motor on rotation is additionally dependent on the position of the load in relation to the linear axis which, on the one hand, hampers control of the bondhead movements and, on the other hand, sets limits on the maximum possible acceleration values.
The object of the invention is to develop a new Wire Bonder whose bondhead withstands considerably higher accelerations.
A Wire Bonder according to the invention contains a bondhead which comprises a slide, a rotary beam rotatable on a vertical axis and a rocker mounted on the rotary beam. The slide is movable back and forth in a predetermined horizontal direction and moves the rotary beam with it. The slide preferably bears on a horizontally arranged glide plate by means of an air bearing charged with vacuum. The rotary beam also preferably bears on the glide plate by means of a further air bearing charged with vacuum. A drive arranged on the slide is preferably foreseen for the rotating movement of the rotary beam.
In the following, embodiments of the invention are explained in more detail.